Testing electrode



N(W. 29, 1927. r 1,650,779

A. F. WILLIAMS T E' STING ELECTRODE.

Filed Jan. 25. 1924 I III/Ii777'7 i 'ing shield'whi'ch Patented Nov. 29,1927..

UNITED ANTHONY F. WILLIAMS, ROCHESTER, NEW YORK, ASSIGNOR TO NORTH EASTELEC- TRIO COMPANY, OF ROCHESTER, NEW YORK, 'A CORPORATION OF NEW. YORK.

'rns'rrne ELECTRODE.

Application filed January 25, 1924. Serial No. 688,486.

This invention relates to electrodes of the I kind used fortestingelectric apparatus for defects such as short-circuits, anddefective insulation. For this purpose it is customary to use manuallyoperated electrodes which are connected with a source of electricity,i-n series with a lampor other indicator, and thetests are made bytouching the contactmembers of the electrodes to the commutatorbars,terminals andother parts of the apparatus under test;

For the-purpose necessary to use high that accidental contact of thetestingin question it is often electrodes with the person'of the user orwith other conductors may cause serious shocks or discharges, and theelectrodes musttherefore be handled with great caution. 5

The. object of I the present inventionis to provide means. whereby thecontact-members of the electrodes are so shielded that accidentalcontacts are rendered. "practically impossible, while at the'same timethe use of the electrodes is not made. in any degree inconvenient. Tothis end it' is proposed to provide a testing-electrode with an'insulat-.contact member whenever the electrode is not in actual use, but whichis automatically withdrawn and held sequence of the act of for thepurpose of using it;

' The idea in question may be embodied in out of the way in convariousways, but the preferred embodiment is illustrated in the accompanyingdrawings, inwhichz. 4. r I Fig. 1 is a-longitudin'al sectional view of atesting-electrode, with the parts in the posiend-elevation, I d Fig. 1-;and Figs.- 3 and 4 are enlarged sectional views on the lines 3-3 and inFig. 1.

.In the illustrated electrode thec'ont-act- .member is a metal. rod 5with a pointed end;

and'the. guard'has the insulating-material such as vulcanized-fiber.

. The electrode-is handled and controlled by i fiber 9r et g-mater el;is

STATES in the sleeve .12 and it passes through the an'electromotiveforce so conductor 15 has its conductive core solderedscrewed .home the cable 15 is firmly gripped 'eration the bushing 18" ispressed against a is in position to guard the members are grasped theygrasping the electrode g of convenient form, and the electrode can tionoccupied'when' not in use; Fig. 215 an looking from left to rightinwhich it is shielded'by the guard; a spring formof a tube 6'of" larguard of insulating-material; a contact- 1,650,779 PATENT OFFICE. v

rear end of the contact-rod 5, thus connectnng this rod with thegrip-member 8. A coiled spring 13, attached to the rear end of the rod5, serves both to retract the rod within the guard, and to connect itwith an electric conductor. A metal nipple 14 is screwed into the rearend of the guard-tube 6, and a cap 16 is threaded upon the rear end ofthe nipple, this cap being of insulatingmaterial. A loose metal bushing18, with a conical rearwardly-opening socket, is enclosed by the cap,and a flexible cable or or otherwise connected with this bushing. Asphtconioal bushing 17 cooperates with thebushlng 18-, so that when thecap 16 is and clamped in place. By the same opcross-pin 19 to'twhich therear end of the spring 13 is attached, thus completing the conductiveconnections between the contactrod 5 and the cable 15.

When the electrodeis not in use the spring acts to hold the contact-rodretracted withi in the guard, as shown, but when the grip-- v arethereby drawn together, thus sliding the rod v'lt'orwardly so that itsend protrudes from the uard. In this position the two grip-membersconstitute substantially a single handle be used precisely the same asthe ordinary unguarded electrode. The moment the electrode is dropped orlaid down, however,'the contact-rod is automatically withdrawn into aposition of safety.

The invention claimed is: 1. -A testing-electrode comprising: a guard;a. contact-member movable, relatively to the guard, into and out of aposition in tending to move the contact-member into shielded position;and grasping-means, suit- 1 able for manipulating the electrode, con-vnected with'the guard'and the contact-member and movable, in consequenceof being ed in the hand of the user, to cause movement of thecontact-member into erative, unshielded position.

2. A testing-electrode comprising: a; tuburod slidably mounted. intherguard; a spring tendi g o re ract he con 4 trod m, 1 1* guard; and ahandle connected with the rod and movable in consequence of beinggrasped in the hand of the user, to cause the rod to protrude from theguard.

3. A testing-electrode, as set forth in claim 2, in which the saidhandle'comprises two grip-members attached, respectively, to the guardand the contact-rod and movable toward each other when grasped.

4. A testing-electrode comprising: a tube, of insulating material, witha transverse slot ,near its rear end; a contact-rod 'slidable withinsaid tube; a sleeve slidable upon the outside of the tube; a pinconnecting said rod and sleeve through said slot; a grip memberprojecting laterally from the sleeve;

a second grip-member fixed to the tube; and a spring for movmg thecontact rod in a direction to retract it within the tube and to separatethe grip-members.

' 5. A testing-electrode comprising: a tube tube of insulating material;a contact-rod normally housed, at its forward end, within said tube butslidabl'e therein to cause said end to protrude from the tube; agrip-member rigidly attached to the tube and extending substantially ata right angle therefrom;

a member attached to the rod, slidably:

guided by the tube and provided with a second grip-member substantiallyparallel with the first said grip-member; and a spring interconnectingthe tube and the slidable members and acting to retract the rod withinthe tube.

ANTHONY F. WILLIAMS.

